-
PloS One 2024NDM-producing carbapenem-resistant bacterial infections became a challenge for clinicians. Combination therapy of aztreonam and ceftazidime-avibactam is a prudent choice...
NDM-producing carbapenem-resistant bacterial infections became a challenge for clinicians. Combination therapy of aztreonam and ceftazidime-avibactam is a prudent choice for these infections. However, there is still no recommendation of a practically feasible method for testing aztreonam and ceftazidime-avibactam synergy. We proposed a simple method for testing aztreonam and ceftazidime-avibactam synergy and compared it with reference broth micro-dilution and other methods. Carbapenem-resistant Enterobacterales clinical isolates were screened for the presence of the NDM gene by the Carba R test. NDM harbouring isolates were tested for aztreonam and ceftazidime-avibactam synergy by broth microdilution (reference method), E strip-disc diffusion, double disc diffusion, and disc replacement methods. In the newly proposed method, the MHA medium was supplemented with ceftazidime-avibactam (corresponding to an aztreonam concentration of 4μg/ml). The MHA medium was then inoculated with the standard inoculum (0.5 McFarland) of the test organism. An AZT disc (30 μg) was placed on the supplemented MHA medium, and the medium was incubated overnight at 37°C. Aztreonam zone diameter on the supplemented MHA medium (in the presence of ceftazidime-avibactam) was compared with that from a standard disc diffusion plate (without ceftazidime-avibactam), performed in parallel. Interpretation of synergy was based on the restoration of aztreonam zone diameter (in the presence of ceftazidime-avibactam) crossing the CLSI susceptibility breakpoint, i.e., ≥ 21 mm. Of 37 carbapenem-resistant NDM-producing isolates, 35 (94.6%) were resistant to aztreonam and tested synergy positive by the proposed method. Its sensitivity and specificity were 97.14% and 100%, respectively. Cohen's kappa value showed substantial agreement of the reference method with the proposed method (κ = 0.78) but no other methods. The proposed method is simple, easily interpretable, and showed excellent sensitivity, specificity, and agreement with the reference method. Therefore, the new method is feasible and reliable for testing aztreonam synergy with avibactam in NDM-producing Enterobacterales.
Topics: Ceftazidime; Aztreonam; Azabicyclo Compounds; Drug Combinations; beta-Lactamases; Microbial Sensitivity Tests; Anti-Bacterial Agents; Enterobacteriaceae; Humans; Drug Synergism; Enterobacteriaceae Infections
PubMed: 38758757
DOI: 10.1371/journal.pone.0303753 -
Microbiology Spectrum May 2024A total of 334 isolates were recovered from 6,223 pet rectal samples collected at 50 pet clinics, 42 pet shops, 7 residential areas, and 4 plazas. Forty serovars were...
A total of 334 isolates were recovered from 6,223 pet rectal samples collected at 50 pet clinics, 42 pet shops, 7 residential areas, and 4 plazas. Forty serovars were identified that included all strains except for one isolate that did not cluster via self-agglutination, with Typhimurium monophasic variant, Kentucky, Enteritidis, Pomona, and Give being the predominant serovars. Fifty-one sequence types were identified among the isolates, and ST198, ST11, ST19, ST451, ST34, and ST155 were the most common. The top four dominant antimicrobials to which isolates were resistant were sulfisoxazole, ampicillin, doxycycline, and tetracycline, and 217 isolates exhibited multidrug resistance. The prevalence of β-lactamase genes in isolates was 59.6%, and among these isolates, 185 harbored , followed by (66) and (10). Moreover, six PMQR genes, namely, including (4.8%), (4.2%), (0.9%), (18.9%), (16.5%), and (1.5%), were detected. QRDR mutations (76.6%) were very common in isolates, with the most frequent mutation in (T57S) (47.3%). Furthermore, we detected six tetracycline resistance genes in 176 isolates, namely, (A) (39.5%), (B) (8.1%), (M) (7.7%), (D) (5.4%), (J) (3.3%), and (C) (1.8%), and three sulfonamide resistance genes in 303 isolates, namely, (84.4%), (31.1%), and (4.2%). Finally, we found 86 isolates simultaneously harboring four types of resistance genes that cotransferred 2-7 resistance genes to recipient bacteria. The frequent occurrence of antimicrobial resistance, particularly in dogs and cats, suggests that antibiotic misuse may be driving multidrug-resistant among pets.IMPORTANCEPet-associated human salmonellosis has been reported for many years, and antimicrobial resistance in pet-associated has become a serious public health problem and has attracted increasing attention. There are no reports of from pets and their antimicrobial resistance in Chongqing, China. In this study, we investigated the prevalence, serovar diversity, sequence types, and antimicrobial resistance of strains isolated from pet fecal samples in Chongqing. In addition, β-lactamase, QRDR, PMQR, tetracycline and sulfonamide resistance genes, and mutations in QRDRs in isolates were examined. Our findings demonstrated the diversity of serovars and sequence types of isolates. The isolates were widely resistant to antimicrobials, notably with a high proportion of multidrug-resistant strains, which highlights the potential direct or indirect transmission of multidrug-resistant from pets to humans. Furthermore, resistance genes were widely prevalent in the isolates, and most of the resistance genes were spread horizontally between strains.
PubMed: 38757951
DOI: 10.1128/spectrum.03542-23 -
Scientific Reports May 2024Β-lactamases-producing Escherichia coli are a widely distributed source of antimicrobial resistance (AMR), for animals and humans. Little is known about the sensitivity...
Β-lactamases-producing Escherichia coli are a widely distributed source of antimicrobial resistance (AMR), for animals and humans. Little is known about the sensitivity profile and genetic characteristics of E. coli strains isolated from domestic cats. We report a cross-sectional study that evaluated E. coli strains isolated from domestic cats in Panama. For this study the following antibiotics were analyzed: ampicillin, amoxicillin-clavulanate cefepime, cefotaxime, cefoxitin, ceftazidime, aztreonam, imipenem, gentamicin, kanamycin, streptomycin, tetracycline, ciprofloxacin, nalidixic acid, trimethoprim-sulfamethoxazole, and chloramphenicol. The data obtained were classified as resistant, intermediate, or sensitive. MDR strains were established when the strain presented resistance to at least one antibiotic from three or more antimicrobial classes. Forty-eight E. coli isolates were obtained, of which 80% presented resistance to at least one of the antibiotics analyzed, while only 20% were sensitive to all (p = 0.0001). The most common resistance was to gentamicin (58%). Twenty-nine percent were identified as multidrug-resistant isolates and 4% with extended spectrum beta-lactamase phenotype. The genes blaTEM (39%), blaMOX(16%), blaACC (16%) and blaEBC (8%) were detected. Plasmid-mediated resistance qnrB (25%) and qnrA (13%) are reported. The most frequent sequence types (STs) being ST399 and we reported 5 new STs. Our results suggest that in intestinal strains of E. coli isolated from domestic cats there is a high frequency of AMR.
Topics: Animals; Cats; Escherichia coli; Drug Resistance, Multiple, Bacterial; Anti-Bacterial Agents; Microbial Sensitivity Tests; Phenotype; beta-Lactamases; Cross-Sectional Studies; Escherichia coli Infections; Genetic Variation
PubMed: 38755240
DOI: 10.1038/s41598-024-62037-8 -
PloS One 2024Cluster regularly interspaced short palindromic repeats and CRISPR associated protein 9 (CRISPR-Cas9) is a promising tool for antimicrobial re-sensitization by...
Cluster regularly interspaced short palindromic repeats and CRISPR associated protein 9 (CRISPR-Cas9) is a promising tool for antimicrobial re-sensitization by inactivating antimicrobial resistance (AMR) genes of bacteria. Here, we programmed CRISPR-Cas9 with common spacers to target predominant blaCTX-M variants in group 1 and group 9 and their promoter in an Escherichia coli model. The CRISPR-Cas9 was delivered by non-replicative phagemid particles from a two-step process, including insertion of spacer in CRISPR and construction of phagemid vector. Spacers targeting blaCTX-M promoters and internal sequences of blaCTX-M group 1 (blaCTX-M-15 and -55) and group 9 (blaCTX-M-14, -27, -65, and -90) were cloned into pCRISPR and phagemid pRC319 for spacer evaluation and phagemid particle production. Re-sensitization and plasmid clearance were mediated by the spacers targeting internal sequences of each group, resulting in 3 log10 to 4 log10 reduction of the ratio of resistant cells, but not by those targeting the promoters. The CRISPR-Cas9 delivered by modified ΦRC319 particles were capable of re-sensitizing E. coli K-12 carrying either blaCTX-M group 1 or group 9 in a dose-dependent manner from 0.1 to 100 multiplicity of infection (MOI). In conclusion, CRISPR-Cas9 system programmed with well-designed spacers targeting multiple variants of AMR gene along with a phage-based delivery system could eliminate the widespread blaCTX-M genes for efficacy restoration of available third-generation cephalosporins by reversal of resistance in bacteria.
Topics: CRISPR-Cas Systems; Escherichia coli; Bacteriophages; beta-Lactamases; Escherichia coli Proteins; Plasmids; Promoter Regions, Genetic; Gene Editing; Anti-Bacterial Agents
PubMed: 38753729
DOI: 10.1371/journal.pone.0303555 -
JPMA. the Journal of the Pakistan... Apr 2024To probe cervical cancer screening practices in local women positive for human immunodeficiency virus, and to determine the cervical cytological changes in them.
OBJECTIVES
To probe cervical cancer screening practices in local women positive for human immunodeficiency virus, and to determine the cervical cytological changes in them.
METHODS
The serial cross-sectional study was conducted at the Jinnah Hospital and Services Hospital, Lahore, Pakistan, from April 2019 to October 2020, and comprised female patients aged 18-45 years who were positive for human immunodeficiency virus or acquired immunodeficiency syndrome and were registered with the relevant programme being run by the provincial government in Punjab. Blood samples of all the patients were collected for the determination of human immunodeficiency virus viral load and cluster of differentiation 4+ count. Cervical smears were taken for cytopathological analysis, while the swabs were analysed for culture sensitivity. The same individuals were subjected to the same testing one year later, and the status of the disease and clinical stability or disease progression was explored. Data was analysed using SPSS 25.
RESULTS
There were 150 women with mean age 32.08±7.13 years (range: 21-45 years). Age at marriage/sexual activity was 17.33±4.73 years in 15(10%) subjects. Cytological examination showed atypical squamous cells of undetermined significance in 6(4%) of the cases whereas 3(2%) cases showed atypical squamous cells, which cannot rule out high grade squamous intraepithelial lesion on cytology, while the rest were classified as negative for intraepithelial lesion or malignancy. Cervical microbial changes revealed methicillin-resistant staphylococcus aureus infection in 9(6%) cases, extended-spectrum beta-lactamase in 15(10%) cases, whereas fungal infection and trichomonas vaginalis infection were found in 30(20%) smears. There was a significant association between cluster of differentiation 4+ cell count and stability of high-risk patients (p<0.001). After one year, 84(56%) patients remained clinically stable, while 51(34%) developed some chronic illness. There was a significant association between cluster of differentiation 4+ cell count <200/mm3 and the risk of developing a chronic illness (p<0.001).
CONCLUSIONS
There was a dire need to educate healthcare workers to offer regular cervical screening to patients with high-risk sexually-transmitted infections to prevent them from the morbidity and mortality related to cervical cancer.
Topics: Humans; Female; Adult; Uterine Cervical Neoplasms; Pakistan; Early Detection of Cancer; Cross-Sectional Studies; Young Adult; Middle Aged; HIV Infections; Vaginal Smears; Uterine Cervical Dysplasia; Atypical Squamous Cells of the Cervix; Viral Load
PubMed: 38751253
DOI: 10.47391/JPMA.8211 -
Nature Communications May 2024Plasmids carrying antibiotic resistance genes (ARG) are the main mechanism of resistance dissemination in Enterobacterales. However, the fitness-resistance trade-off may...
Plasmids carrying antibiotic resistance genes (ARG) are the main mechanism of resistance dissemination in Enterobacterales. However, the fitness-resistance trade-off may result in their elimination. Chromosomal integration of ARGs preserves resistance advantage while relieving the selective pressure for keeping costly plasmids. In some bacterial lineages, such as carbapenemase producing sequence type ST38 Escherichia coli, most ARGs are chromosomally integrated. Here we reproduce by experimental evolution the mobilisation of the carbapenemase bla gene from the pOXA-48 plasmid into the chromosome. We demonstrate that this integration depends on a plasmid-induced fitness cost, a mobile genetic structure embedding the ARG and a novel antiplasmid system ApsAB actively involved in pOXA-48 destabilization. We show that ApsAB targets high and low-copy number plasmids. ApsAB combines a nuclease/helicase protein and a novel type of Argonaute-like protein. It belongs to a family of defense systems broadly distributed among bacteria, which might have a strong ecological impact on plasmid diffusion.
Topics: Plasmids; beta-Lactamases; Escherichia coli; Escherichia coli Proteins; Bacterial Proteins; Anti-Bacterial Agents; Drug Resistance, Bacterial; Chromosomes, Bacterial
PubMed: 38750030
DOI: 10.1038/s41467-024-48219-y -
Frontiers in Microbiology 2024In recent decades, widespread multi-drug resistant (MDR) bacteria have become a serious problem in healthcare facilities.
INTRODUCTION
In recent decades, widespread multi-drug resistant (MDR) bacteria have become a serious problem in healthcare facilities.
METHODS
To systematically summarize and investigate the prevalence and genomic features of clinical MDR () clinical isolates recovered from the first hospital of Lanzhou University, we collected 50 MDR isolates isolated in the first quarter of 2022 and using whole-genome sequencing investigate the genotypic characteristics.
RESULTS
All of these isolates were generally resistant to the common β-lactamase antibiotics. Resistance to cefoperazone-sulbactam varies greatly between different clones. The proportion of CC208 isolates resistant and mediated to cefoperazone-sulbactam is as high as 84.6%. There were no isolates resistant to tigecycline and colistin. The presence of (94.0%) and (98.0%) were the most frequent determinants for carbapenem resistance. Two main endemic clones were identified, one (ST469) was predominantly circulating in ICUs and carried the same resistance genes, virulence genes and transposons, and the other clone (CC208) carried more resistance genes and had more widely disseminated.
DISCUSSION
Our study showed that clinical MDR isolates circulating in our hospital exhibited highly similar genetic features. We should take timely and effective measures to control the further epidemic of these isolates.
PubMed: 38746749
DOI: 10.3389/fmicb.2024.1293725 -
One Health (Amsterdam, Netherlands) Jun 2024Multi-host communities are perfect scenarios for the emergence and spread of pathogens, threatening the recovery of endangered, isolated, or inbred populations, such as...
Multi-host communities are perfect scenarios for the emergence and spread of pathogens, threatening the recovery of endangered, isolated, or inbred populations, such as the brown bear () in northwestern Spain. The population recovery in recent years has forced bears to occupy highly anthropized areas, increasing their interaction with human and domestic animals, with potential consequences for global health. During 2022-2023 a survey of parasites, bacteria and viruses shared between wildlife, domestic animals and humans was performed in this population using non-invasive surveillance, i.e., bear fecal samples ( = 73) and sponge-based sampling of trees ( = 42; 14 rubbed trees and 28 control trees). Pathogen detection rates were defined as the percentage of qPCR or culture-positive samples. Generalized linear models were fitted to assess their relationship with environmental variables including dispersion of the human population, and percentage of agricultural and periurban habitats in a 6 km-buffer around each sample. Canine Adenovirus type 1 (45.2%), spp. (15.1%), spp. (12.3%), and extended-spectrum-beta-lactamases (ESBL) (1.4%) were identified in fecal samples. In contrast, only five sponges from three rubbed and two control trees resulted positive to (14.3%). The results suggest that several pathogens are common in the Cantabrian brown bear population and that anthropization of the territory modulates their prevalence and richness. The effective design of management programs for bear conservation will require a one-health approach, in which genetic analysis of non-invasive samples can be key tools for the sanitary surveillance at the wildlife-livestock-human interface.
PubMed: 38746539
DOI: 10.1016/j.onehlt.2024.100746 -
BioRxiv : the Preprint Server For... May 2024Several enzymes from the metallo-β-lactamase-like family of lactonases (MLLs) degrade acyl-L-homoserine lactones (AHLs). In doing so, they play a role in a microbial...
Several enzymes from the metallo-β-lactamase-like family of lactonases (MLLs) degrade acyl-L-homoserine lactones (AHLs). In doing so, they play a role in a microbial communication system, quorum sensing, which contributes to pathogenicity and biofilm formation. There is currently great interest in designing quorum quenching ( ) enzymes that can interfere with this communication and be used in a range of industrial and biomedical applications. However, tailoring these enzymes for specific targets requires a thorough understanding of their mechanisms and the physicochemical properties that determine their substrate specificities. We present here a detailed biochemical, computational, and structural study of the MLL GcL, which is highly proficient, thermostable, and has broad substrate specificity. Strikingly, we show that GcL does not only accept a broad range of substrates but is also capable of utilizing different reaction mechanisms that are differentially used in function of the substrate structure or the remodeling of the active site mutations. Comparison of GcL to other lactonases such as AiiA and AaL demonstrates similar mechanistic promiscuity, suggesting this is a shared feature across lactonases in this enzyme family. Mechanistic promiscuity has previously been observed in the lactonase/paraoxonase PON1, as well as with protein tyrosine phosphatases that operate a dual general-acid mechanism. The apparent prevalence of this phenomenon is significant from both a biochemical and an engineering perspective: in addition to optimizing for specific substrates, it is possible to optimize for specific mechanisms, opening new doors not just for the design of novel quorum quenching enzymes, but also of other mechanistically promiscuous enzymes.
PubMed: 38746346
DOI: 10.1101/2024.05.01.592096 -
BMC Microbiology May 2024Multidrug-resistant (MDR) P. aeruginosa is a rising public health concern, challenging the treatment of such a ubiquitous pathogen with monotherapeutic anti-pseudomonal...
BACKGROUND
Multidrug-resistant (MDR) P. aeruginosa is a rising public health concern, challenging the treatment of such a ubiquitous pathogen with monotherapeutic anti-pseudomonal agents. Worryingly, its genome plasticity contributes to the emergence of P. aeruginosa expressing different resistant phenotypes and is now responsible for notable epidemics within hospital settings. Considering this, we aimed to evaluate the synergistic combination of fortimicin with other traditional anti-pseudomonal agents and to analyze the resistome of pan-drug resistant (PDR) isolate.
METHODS
Standard methods were used for analyzing the antimicrobial susceptibility tests. The checkerboard technique was used for the in vitro assessment of fortimicin antibiotic combinations against 51 MDR P. aeruginosa and whole genome sequencing was used to determine the resistome of PDR isolate.
RESULTS
Out of 51 MDR P. aeruginosa, the highest synergistic effect was recorded for a combination of fortimicin with β-lactam group as meropenem, ceftazidime, and aztreonam at 71%, 59% and 43%, respectively. Of note, 56.8%, 39.2%, and 37.2% of the tested MDR isolates that had synergistic effects were also resistant to meropenem, ceftazidime, and aztreonam, respectively. The highest additive effects were recorded for combining fortimicin with amikacin (69%) and cefepime (44%) against MDR P. aeruginosa. Resistome analysis of the PDR isolate reflected its association with the antibiotic resistance phenotype. It ensured the presence of a wide variety of antibiotic-resistant genes (β-lactamases, aminoglycosides modifying enzymes, and efflux pump), rendering the isolate resistant to all clinically relevant anti-pseudomonal agents.
CONCLUSION
Fortimicin in combination with classical anti-pseudomonal agents had shown promising synergistic activity against MDR P. aeruginosa. Resistome profiling of PDR P. aeruginosa enhanced the rapid identification of antibiotic resistance genes that are likely linked to the appearance of this resistant phenotype and may pave the way to tackle antimicrobial resistance issues shortly.
Topics: Pseudomonas aeruginosa; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Whole Genome Sequencing; Humans; Genome, Bacterial; Drug Synergism; Pseudomonas Infections
PubMed: 38745145
DOI: 10.1186/s12866-024-03316-2